Enrichening device



Filed April 4, 1945 A. W. ORR, JR

ENRICHENING DEVICE v 2 Sheets-Sheet 1 INVENTOR.

W ATTORNEY.

Patented May 3, i949 snmcnnmo Davies A. William Orr, In, Detroit, Micln, assignor to George liL Holley and Earl Holley Application April 4, 1945, Serial No. 586,606

3 Claims. 1

The object of this invention is to provide an enrichening device which adds a certain amount to the fuel when the mixture is set for cruising lean, and when set for cruising rich, the enrichening device is only permitted to add a less amount. For example, if the cruising lean mixture is .065, then a 57% enrichment gives .102 mixture. If cruising rich is .08, thena 27% enrichment gives .102 mixture.

An additional object is to provide for the acceleration requirements and to incorporate means whereby when the manual control lever is moved from the cruising lean" to the idle cut-out position the acceleration means are eliminated.

Another additional object is to substitute water or other anti-detonating fuels for a portion of the enrichening fuel. The quantity of this water is regulated by the flow of fuel and air so that the consumption of water is held to a minimum.

Figure 1 shows diagrammatically my invention incorporated in an airplane carburetor.

Figure 2 shows the fuel/air ratio at various air flows and the effect of the addition of water at high air flows on the fuel/air ratio. This application contains subject matter common to Serial No. 581,644 filed March 8, 1945 now patent 2,465,535 of March 29, 1949, by George M. Holley, Jr. and this application is directed chiefly to the disclosure contained in the lower part and on the left portion of Fig. 1.

In Fig. 1, II] is the air entrance, I I is the throat of a venturi, I2 is the throttle, which, when moved to the left counter-clockwise, converts the venturi II into a variable venturi, I3 is an opening into the throat of the variable venturi II-I2, thus formed, I4 is a passage connecting the orifice I3 with the chamber I6, I5 is a passage parallel to and below the passage I4 and connecting the orifice I3 with the chamber I1, I8 is a diaphragm above the chamber I6, I9 is a passage connecting the annular chamber with a chamber 2| immediately above the diaphragm I8, springs 22 and 23 support the diaphragm I8, which carries a metering needle 24, which controls the connection between the chamber I6 and a passage 25. The annular chamber 20 is in communication with the air entrance Illthrough a large number of openings 26, so that the pressure of the air entrance exists in the chamber 2 I.

This pressure of the air entering the-carburetor also-exists in a similar chamber 21, in which there is a similar spring 28 and a diaphragm 29 corresponding to the diaphragm I8, and a spring 30 corresponding to the spring 23, and a metering needle 3| corresponding to the needle 24. This H in the automatic lean position, as shown, ob-

2 needle 3| forms a restricted communication between the chamber II below the diaphragm 23 and a passage 32, which communicates through a restriction 33 with the air inlet pressure line I9. The passage 32 communicates with a chamber 34, the passage 25 communicates with a chamber 36, so that a diaphragm 31, which separates the chamber 34 from the chamber 36, is supported on one side by the pressure in the pipe 32 and on the other side by the suction in the pipe 25. The pressure in the chamber 34 is higher than the pressure in the'passage 25; that is to say, the

valve 24 is normally opened to such a degree as to admit a good deal of the suction in pipe I4 to the chamber. 36, whereas the valve 3| is normally closed and only opens at comparatively high suctions, so that substantially atmospheric pressure exists in chamber 34.

A chamber 38, in free communication with the annular chamber 20, contains a group of altitude bellows 39, which, at altitude, expand and cause the valve 40 to move to the left, compressing the spring 4|. The valve 40, whichis a balanced valve, thenadmits a restrictedamount of atmospheric air to the passage 25, which as stated above is a suction passage, so that when the bellows 39 expand due to a lowering of the atmospheric pressure in the entrance III, the pressure in the pipe 25 rises relative to the pressure in the pipe 32, which is not affected by the bellows 39. At altitude, the influence of the air flow on the diaphragm 31 is thus diminished, and the mixture ratiois thus maintained withinthe desired limits.

The throttle I2 is rotated by the throttle lever 42, which is connected to the link 43, which in its turn is connected to the link 44 to the lever 45. This lever 45 and its control disc 46 are shown turned clockwise into a position approaching the wide-open throttle position and thus partially open fuel metering orifices 41 and 43, which admit metered fuel to passages 49 and 50. The valve structs the flow through the restriction 41 and passage 50 by closing the port I55, but permits that metered by the opening 48 through the passage 49 to flow into the chamber 53 through the open port I54. This metered fuel, together with the small quantity of fuel which flows through a bypass 5I past a low speed adjusting needle 52 into passage 49, communicates through the port I54 with the chamber 53 to the right of a diaphragm 54, which is to the right of the fuel entrance chamber 55, which communicates with a fuel entrance 56 through a fuel venturi 51. Hence,-

the'passages 93 and ing past the restriction 48.

11 is moved counter-clockwise 45 to open port I55 to the automatic rich position.

The pilot valve 58 engages through the diaphragm 62 with the pin 59, which engages through the diaphragm 31 with the pin 66, which pin 66 engages through the small diaphragm I56 with the pin 6|. In order that the flow shall be regulated, pilot valve 58 controls the flow of metered fuel from an orifice 63 through a passage 64, past valve 58 to a passage 61, which communicates with a, chamber 69 below the valve 66. The pressure in the passage 64 and in a chamber 65 connected thereto is equal to the pressure of the metered fuel in the passage 49 less the drop at the restriction 63. This drop is controlled by the valve 58. The pressure thus regulated in chamber 65 acts on a diaphragm I49, and a spring 266 tends to seat the valve 66. When the flow is excessive compared with the air flow, then the fuel pressure acting on the diaphragm 54 pushes Q phragm 31.

the direction of closing as diaphragms 54 and 31 entrance 56 through the passage 91.

the valve 58 over to the right, overcoming the air pressure diiference due to air flow acting on diaphragm 31. The valves 66 and 58 then partly close as diaphragms 54 and 31 move to the right.

The fuel, thus metered, flows to the outlet chamber 69, in which is located a valve 16, mounted on a diaphragm 14, to the left-hand side of which is a chamber, which communicates through the passage 12 with the unmetered fuel in chamber 55.

A spring 13 tends to push the diaphragm 14 to the left and thus opens the valve 16, which allows fuel to flow through the passage I48 past the cut-off valve 15 to the outlet 16.

The mixture control valve 11 is controlled by a. lever 18 and a link 19, which also controls cutoff valve 15 through the lever 86. When the valve 11 moves clockwise, it moves into the idle cut-01f position; when it moves counterclockwise, it moves to the automatic rich position (A. R.). As shown, it is in the automatic lean position. When valve 11 is rotated anti-clockwise fuel is admitted from the variable restriction 41, so that the fuel flow through both 48.-and 41 controls the pressure in chamber 53. This is the automatic rich position (A. R).

Valve 11 and link 19 are connected through the link 84 to the lever 85, which controls the rotation of the valve 86. In the position shown in which the mixture control valve 11 closes port I55, the outlet 41 is closed and fuel is admitted only through the passage 48. In that position, the valve 86 forms a path from the passage 81 to the L shaped passage 88, which communicates with the passage 89 and also with the passage 96. These passages 89 and 96 communicate through the restriction 9| and through the restriction 92 to the passages 93 and I93 and so to the chamber 94, which communicates with the chamber 69, so that any fuel flowing through I93 is added to the fuel flow- Valve 66 is seated by a spring I66 and also by the pressure in the chamber 65 connected to the passage 64. This pressure acts on the upper side of the diaphragm I49. The under portion of the valve 66 is subjected to the pressure in the passage 49 acting through the port I 54. The pressure in 65 is regulated by the valve 58. Hence, the valve 58 controls the movement of the valve 66. Hence, when the fuel flow is excessive compared with the air flow, then the fuel flow acting on the diaphragm 54 is great compared with the air pressure due to air flow acting on the dia- The valves 58 and 66 then move in are moved to the right. This arrangement will give a constant fuel/ air ratio. The fuel/ air ratio must progressively become richer as the fuel flow and air flow increase. Otherwise, the engines would become overheated. Obviously, at maximum fuel flow and at maximum air flow, fuel economy is of minor importance, the major importance being given to power and the greatest importance being given to preventing the engine burning up, and, of course, a rich mixture is much cooler than a mixture which gives perfect combustion.

The fuel flowing through 81 flows out of the chamber 95 to the right of the diaphragm 96, which chamber 95 communicates with the fuel The fuel flow through the restriction 92 and passage 93 escapes through the restriction I18. I19 is an opening in the pipe I93 corresponding to the opening I18 in the pipe 93. The chamber 98, to the left of diaphragm 96, communicates with the throat of the venturi 51 through the restricted orifice 99. Valve I66 is carried by the diaphragm 96 and is seated by a compression spring I6I in the chamber 98, so that the flow through the venturi 51 must be great enough to compress the spring I6I; otherwise, the valve I66 will not open, so that the valve I66 only opens at high air flows and when the fuel flow is correspondingly high.

A passage I62 connects with the restricted orifice 99, and in the position shown is inoperative. When the lever is ,moved counter-clockwise into the automatic rich'position (A. R.) an opening I63 in valve 86.-a1lows fuel to flow towards orifice 99 .and along the passage I62 from the passage I641 The jet numbered I66, located in the passage I64, is an important restriction in the fuel metering system? Restriction 99 is inserted only to make the jet I66 of small enough size. The flow through the restriction I66, through the passage I63, through the passage I62, increases the pressure in the chamber 98, so that the valve I66 will not open so much in the cruising rich position for the same fuel flow through the venturi 51. Jet 99 can be omitted if the suction holes in the venturi throat 51 are of the proper size and are held to close limits in production.

The passage I 64 communicates with the unmetered fuel in the chamber 55 so that when the lever 85 .is moved counter-clockwise to the automatic rich position (A. R.), a certain amount of fuel flows from the chamber 55 through the passage I64, through the restricted orifice I63,

to the passage I62, and so the pressure in the chamber 98 rises. Hence, the valve I 66 closes slightly, and the combined effect of rotating the lever 85 counter-clockwise is to open valve 11 so as to admit fuel from port 41 and by rotating valve 86 to cut off the fuel flowing through 89 and restrict the fuel to the capacity of the restriction 9I. In addition, the operating pressure difference, which causes the valve I66 to move to the left to open, is no longer as powerful because of the back bleed from I64 through I66, I63, up I62, through 99 to the throat of venturi 51.

When anti-detonating liquid is required to obtain military output, the practice is to cut down the fuel added by the power enrichment venturi 51, valve I66 and passages 81, 89, 96

I18 and I19.

and 93. The pressure of this anti-detonation liquid, water, for example, is applied through a Anti-detonation fluid Anti-detonating fluid, water, for example, contained in the bottom of the tank I16, is admitted through the pipe I6I past the valve I62, which is controlled by the solenoid I63 and the manuallycontrolled switch I66. The outlet from'the valve I62 branches, branch I06 going to the chamber I06 containing the diaphragm I01, thus compressing the. spring I08 and closing the outlet from the passages 93 and I93 as already described. Branch I66 flows around the valve I66, which is held against the flat of the cam I61 by the compression spring I68. The cam I61 is moved by the throttle lever 62. The antl-detonating fluid (water), contained in the bottom of the tank I16, then flows past valve I69 through the passage I10 to the chamber 69. A diaphragm I1I controls the valve I69. A chamber I12 to the right of the diaphragm "I is connected by the passage I13 to the chamber 63. The chamber 216, located on the other side of diaphragm "I, is subjected to the pressure downstream of the valve I66. The gasoline in the upper part of the tank-I16 is at the pressure of the fuel entering the carburetor through the passage 66 because of the opening 219 provided to connect the pipe I16 to the tank I16. An engine-driven pump I16 supplies fuel through the passage I16 from fueientrance 260 to the upper part of the tank I16 and also to the fuel entrance of the carburetor through the pipe I16 and passage 66. A spring-loaded pressure relief valve I11 regulates the pressure in tank I". When the diaphragm I01 closes the outlets from the pipes 93 and I93, a limited quantity of fuel continues to flow through the small orifices Acceleration When the throttle I2 is opened rapidly, the lever I IIO, connected to the throttle I2 and lever 66 by links 63 and 66, is rotated clockwise and supplies pressure through the cam III to the finger 2, which is moved to the right which movement provides accelerating fuel for the engine by hydraulic means not shown.

Passages 6I and 82 areconnected through the passage 83 in the valve 11. When the valve 11 is moved 45 into the idle cut-oil. position, the passage 63 moves clockwise and leaves the two passages and 82 separated from each other. The object of this is that when the attempt is made to stop the engine by placing the valve in the idle cut-off position, the attempt might fail unless the accelerating means were rendered inoperative. The instructions are that when the throttle I2, which is in the position to give approximately 1050 revolutions per minute, is opened, thusflooding the engine with air and rendering the mixture non-explosive, the accelerating device operated by the finger H2 and cam III will automatically function unless the pipe BI is separated from the pipe 82, andit is most undesirable when stopping an engine for the accelerating device to discharge fuel. Moreover, as the engine slows down, the

pressure in the pipe 8I automatically falls, which also is apt to cause the untimely discharge of fuel from the accelerating device, When the accelerating device is used and the wobble pump is used, the increase of pressure in the pipe 6I in the case of the accelerating device will cause the accelerating device to function. For all these reasons. it

is desirable to separate 6| from 82 when 'in the idle cut-ofi position.

Vapor separation The unmetered fuel in the chamber 66 is vented through the passage I36; metered fuel in 63 is vented throughI28. The vapor is thus removed from the upper part of the chambers 63-66. Floats l3I--I32 have integral with them valves which control the orifices I33-I36. Passage I36 communicatw with the air entrance I0 and with the chamber I31 to the left of diaphragm 62 and also with the drain passage I36. Passage I36 also commumcates with the chamber I60 to the right of diaphragm I66, and chamber I60 also communicates with the drain passage I39.

I The passage I9 communicates with the passage I66, which communicates with the chamber I60 on the left-hand side of the diaphragm I66. The passage I9 also communicates with the right-hand side of diaphragm 62, that is, with chamber I69, so that the diaphragms 62 and I66 have the same pressure on each side. 6

Operation is the automatic lean position (cruising lean), the restriction I60 has no function, because in that event the slot I03 has no connection with passage I02. Under these circumstances, all the fuel that can flow through the restrictions 92 and SI is admitted to the engine once the'fuel flow through fuel venturi 61 is big enough to unseat valve I00.

When the lever 86 is moved into the automatic rich. (A. R.) position, approximately 45 anticlockwise from the position shown, their the flow is restricted to that which can flow down pipe 90 and through restriction 9I along the passage I93. It is restricted also because the opening of the valve I00 is delayed as the flow back through I60 to I03 and pipe I02 through 99 to venturi 61 delays the opening of the valve I00 until the critical flow is higher than it was when the. lever 18 was in the automatic lean (A. L.) position shown.

Hence, the rotation anti-clockwise of lever 86 not only reduces the extra flow, but delays the start of the added fuel flow until the main fuel flow is higher than it was with the control in the automatic lean (A. L.) position.

When the mixture control lever is moved into the idle cut-ofl position, 45 clockwise from the automatic lean (A. L.) position in which it is shown, the two passages 3| and 82 become sepagated and the accelerating means become inoperaive.

Again, if the anti-detonating fluidis admitted to the chamber I06 (this fluid being admitted to the engine through passage I6I-I66I10), it is undesirable to have much of the extra fuel from passages 69-9093 admitted through the valve I00 as well as the anti-detonating fluid. Hence,

the diaphragm I01 moves to the left to restrict.

the flow of this extra fuel. The object of the extra fuel admitted past the valve I00 is to prevent In the figure, the admission of the anti-detonating fluid is controlled by the pilot's switch I84 and is determined by the position of the valve I8 which is such that the pressure in the chamher 218 balances the pressure in the chamber I12. The pressure in chamber I12 equals that in chamber 53, which is the downstream pressure of the fuel passing the metering orifice 48 or orifices 41 and 48 if both are effective. The pressure in chamber 218 equals the pressure in the tank I14 less the drop' past the valve I88. The pressure in the chamber 53 likewise equals the pressure in tank I14 less the drop through the metering orifice 48 or orifices 41 and 48,- as the case may be. Hence, as the drop past the valve 48 or past the valves 41 and 48 increases, more water is admitted. This drop in pressure is the operating force of the diaphragm 54. By this means the pressure in the chamber 218 is equal to the pressure in chamber I12. The pressure in I12 is equal to the pressure in chamber 53. Hence, the flow of water is dependent on the difference in fuel pressure between chambers 53 and '55 ignoring the gravity head which is negligible. The passage I65 on the upstream side in the needle I66 is the pressure in the fuel and water tank I14. Therefore, the pressure drop at the needle I I56 corresponds to the pressure drop at the fuel opening 48. Hence, the fuel flow past 48 and the flow past- I88 of water will be in proportion to each other and the flow past the needle I86 will vary with the air fiow through the variable opening between throttle I2 and the wall of the air passage.

This arrangement will therefore give the same air-water ratio whether the control is set for cruising lean or set for cruising rich. With cruising lean, only the orifice 48 is open, but the drop in pressure is determined by the air flow and the fuel pressure drop iscontrolled by the drop in the variable air venturi, which is wide open or nearly so when the water is admitted.

Fuel/air ratios In Figure 2, the curve A E F D represents the F/A ratios when lever 85 is in position shown the vertical ordinates represent the fuel/air ratios; horizontal lines represent percentage of air flow, that is, the percentage of maximum air flow. The point A represents the fuel/air ratio of point I-I at 5% of the normal maximum air flow, the horizontal line BC represents the cruising'rich mixture .080 when the lever 85 is rotated approximately 45 anti-clockwise, the horizontal line EF represents the cruising lean mixture .065, point D, mixture ratio .102, represents the rich mixture, wide open throttle, at 95% of the maximum air fiow. The vertical line D--G represents the reduction in mixture ratio due to the closing of the valve 2" attached to diaphragm I01 on the admission of water and is due to the obstruction of the'flow through the pipes 93 and I93 when water is added. The difference between G and C, which is .007, is due to the opening I19. The difference between G and F, which is .022, is due to the openings I18 and I19.

From G to G from 95-115% air flow, the mixture ratio remains at .087, point C indicates the moment when the valve I00 unseats and responds to the fuel flow .080 at the time when the air fiow A is 60 of the normal maximum air flow. The

point F responds to a fuel flow 20% less, the restriction I 68 is so designed with reference to restriction 99 that the fuel flow at F, which unseats the valve I00, is considerably less than the fuel flow when the mixture ratio is .080,

' 8 which unseats the valve I00 at the point C. Obviously, there is 23% more fuel flow at the point C than there is at the point F. Hence, the fuel flow corresponding tothe point C must be made less effective than the'fuel corresponding to the point F. C and F are both at 60% of normal maximum air flow.

What I claim is:

1. In a carburetor having an air entrance, a. restriction therein, a fuel passage, a restriction therein, automatic means responsive to the drops in pressure in both fuel and air restrictions for maintaining a predetermined mixture ratio of fuel to air, manual means for increasing the fuel flow at the same drop in pressure and thus changing this ratio from cruising lean to a larger ratio for cruising rich, automatic enrichening means responsive to a predetermined high rate of fuel how and adapted to increase the fuel to air mixture ratio, including a second fuel restriction located in series with the first restriction, a chamher, a moving wall therein dividing said chambe? into two portions namely a high pressure portion connected to the fuel pressure on the upstream side of said second fuel restriction, a low pressure portion connected to be subjected to the drop in pressure due to fuel fiow through said second restriction, an enrichening valve conriected to said moving wall, a second fuel passage controlled by said valve and connected in parallel with the first fuel passage so as to admit the enrichening fuel beyond the first restriction, a bypass from the high pressure to the low pressure side of said moving wall, a second manually controlled'valve positively connected to said first manual control valve so that the two valves open together, said second manually controlled valve being located in said bypass so as to reduce, when opened, the pressure difference acting on said moving wall so as to require a higher fuel flow through said second restriction before said enrichening valve will open when the first manually controlled means is moved to its rich position so that the ultimate maximum total fuel flow is the same for all positions of the manual means.

2. In a carburetor having a source of fuel under pressure, a fuel'passage, two variable fuel restrictions in said passage in parallel, a diaphragm, a chamber at the pressure of the entering fuel and located on one side of said diaphragm, the pressure downstream from said restrictions being applied to the other'side, an air entrance, a variable-air restriction therein, a second diaphragm, twobhambers associated therewith, one subjected to the pressure of the entering air, the other to the pressure in the throat of the variable air restriction, said diaphragm being adapted to oppose the movement of first diaphragm, automatic means connected to both diaphragms to control the fuel flow, mechanical means for controlling said variable air and both fuel restrictions simultaneously, a manual mixture control comprising a fuel valve located in series with one of said variable fuel restrictions and adapted to close the outlet from that particular fuel restriction,

now exceeds a predetermined value, said diaphragms and the said automatic means connected to both diaphragms being adapted to increase the quantity of enricheningfuel whenever one of the variable fuel restrictions is blocked so that the cruising lean mixture is enriched by the addition of much more fuel than is added to the cruising mam 9 rich mixture whereby the resulting mixture ratio at maximum air flow is the same whether the control is set for cruising lean or for cruising rich.

3. An engine fuel supply system comprising an air intake, an air restriction therein, a source of fuel under pressure, a fuel supply passage connected thereto, a restriction therein, automatic means responsive to the depression in said air restriction acting in opposition to the means responsive to the drop in pressure at said fuel restriction for varying the pressure downstream from said fuel restriction for maintaining a desired fuel/air ratio, a fuel enrlchening device responsive to an increase in fuel flow above a pre' determined value, a source of anti-detonating fluid under the same pressure as the source of fuel, a passage therefor, a manually controlled valve therein, means for introducing the antidetonating fluid into the air entering the engine comprising a restriction in said anti-detonating fluid passage, a moving wall, a valve in the antidetonating fuel passage connected to said moving wall, a chamber located on one side of said moving wall connected to the anti-detonating fuel passage downstream from said restriction, a second 1Q chamber located on the other side of said moving wall connected to the fuel under pressure existing downstream of said main fuel restriction whereby the drop in pressure at the restriction in said antidetonating fuel passage is maintained equal to the drop in pressure at the restriction in the main fuel passage.

' A. WILLIAM ORR, Jr.

REFERENCES CITED The following references are of record in th file of this patent:

UNITED STATES PATENTS Number Name Date Re. 22,254 Chandler Jan. 26, 1943' 2,381,227 Mock Oct. 24, 1944 2,361,228 Mock Oct.' 24, 1944 2,372,356 Chandler Mar. 27, 1945 FOREIGN PATENTS Number Country Date 828,458 France May 18, 1988 

